RISK MANAGEMENT ACTIVITIES AND FAIR VALUE MEASUREMENTS - DERIVATIVE NOTIONAL AMOUNTS AND FAIR VALUE (Details) - USD ($) $ in Millions	Sep. 30, 2018	Jun. 30, 2018
Derivative [Line Items]
Notional Amount	$ 14,366	$ 13,793
Derivative Asset	185	196
Derivative Liability	(159)	(184)
Foreign Exchange Contract
Derivative [Line Items]
Notional Amount	7,936	7,358
Derivative Asset	42	30
Derivative Liability	21	56
Derivatives in Fair Value Hedging Relationships \| Interest Rate Contracts
Derivative [Line Items]
Notional Amount	4,588	4,587
Derivative Asset	110	125
Derivative Liability	62	53
Derivatives in Net Investment Hedging Relationships
Derivative [Line Items]
Notional Amount	1,842	1,848
Derivative Asset	33	41
Derivative Liability	76	75
Designated as Hedging Instrument
Derivative [Line Items]
Notional Amount	6,430	6,435
Derivative Asset	143	166
Derivative Liability	$ 138	$ 128

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226008-175313

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611

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-SubTopic 20
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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
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-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
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